It also senses the voltage drop across one excitation lead, and then subtracts twice this voltage from the combined total. In 3-wire hookup, the transmitter senses the combined voltage drop across the unknown resistance plus two excitation leads. In 4-wire hookup, different pairs of leads are used to apply the excitation current and sense the voltage drop across the unknown resistance, so that the IR drop across the excitation leads is not a factor. The transmitter applies a fixed excitation current for each resistance range. Resistance Measurement with Excitation & Lead Compensation Ohm transmitter hookup can be via 2, 3 or 4 wires to the J5 connector. Leave 6 mm (1/4") between transmitters, or force air with a fan. Mount transmitters with ventilation holes at top and bottom. Two solid state relays, SPST, normally open, Form AĠ☌ to 55☌ standard, -40☌ to 70☌ with -X option Modbus over Serial Line Specification V1.0 (2002) The applied excitation current is sensed by the meter, which operates in a ratiometric mode and automatically compensates for any changes in excitation.Ġ.02% of output span plus conversion accuracyĢ50V rms working, 2.3 kV rms per 1 minute testģ00, 600, 1200, 2400, 4800, 9600, 19200 baudĢ50V rms working, 2.3 kV rms per 1 min test Low-voltage 10-48 Vdc or 12-32 Vac power is optional. The supply can drive 20 mA into a 500 ohm (or lower) load for 10V compliance, or 10V into a 5K ohm (or higher) load for 2 mA compliance. Output isolation from signal and power grounds eliminates potential ground loop problems. All selections provide 16-bit (0.0015%) resolution of output span and 0.02% output accuracy of a reading from -99,999 to +99,999 counts that is also transmitted digitally. 4-20 mA, 0-20 mA or 0-10V analog transmitter output, isolated, jumper-selectable and user scalable.Note that RS232 or RS485 data I/O is provided by Laurel's LT Series transmitters. The supported protocols are Modbus RTU and ASCII, which are tunneled via Modbus TCP. Standard features of Laureate LTE transmitters include: Linearization is provided by curvilinear spline fits, and the reading can be scaled in software for user-selected engineering units of measure. Peak and valley values are automatically captured and may be displayed via a front panel pushbutton command or a control signal at the rear connector, or be transmitted as serial data.Ĭustom curve linearization, available with the Extended version, makes this transmitter suitable for use with transducers whose output is a non-linear changing resistance. High read rates are ideal for high-throughput manufacturing processes. High read rates at up to 60 or 50 conversions per second while integrating the signal over a full power cycle are provided by Concurrent Slope (US Pat 5,262,780) analog-to-digital conversion. If desired, the transmitter can easily be calibrated using external standards plus scale and offset in software. This allows ranges and signal conditioner boards to be changed in the field without recalibrating the transmitter. This technique effectively subtracts the lead resistance if the excitation leads are the same.Īll resistance ranges are digitally calibrated at the factory, with calibration factors stored in EEPROM on the signal conditioner board. With 3-wire hookup, the transmitter senses the combined voltage drop across the RTD plus two excitation leads. With 4-wire hookup, 2 wires are used for excitation and two separate wires are used to sense the voltage across the resistance to be measured, thereby eliminating any lead resistance effects. Transmitter connections can be via 2, 3 or 4 wires. In the 2 ohm range, resolution is 0.1 milliohm for contact resistance measurements. Accuracy is an exceptional ☐.01% of reading ± 2 counts. Factory-special, fixed ranges of 2.0000 ohm, 2.0000 Mohm and 20.000 Mohm are also available. It is factory calibrated for five jumper selectable resistance ranges from 20.000 ohm to 200.00 kohm. The Laureate Resistance Transmitter is ideal for high-speed, high-accuracy resistance measurements in a production environment, such as contact resistance measurements.
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